Antarctic Research Program Research Articles

Silica spherules in Late Pleistocene‑Holocene glaciomarine sediments from the Ross Sea, Antarctica: insights into the formation and significance

In this study, we investigate silica spherules with a diameter <1.25 mm from sediment cores retrieved from the northern Drygalski Trough, during the Italian Antarctic Research Programme (PNRA) expeditions in 1999 and 2002. In the past, these unique spherules have been a subject of interest due to their distinctive characteristics. Despite previous hypotheses on their origin, a comprehensive discussion on their formation mechanism and implications in marine sediments was lacking. Our analysis encompasses the depositional environment, morphology, internal texture, major element composition, and age determination through radiocarbon dating (14C) and 40Ar‑39Ar dating of spherule-containing sediments. By integrating our findings with a critical review of existing literature, we propose that spherules form by cyclical chemical precipitation of silica when silica‑rich freshwater mixed with seawater during extensive events of ice melting. We also tentatively suggest that these spherules possibly represent a proxy for significant meltwater production and discharge into the Antarctic Ocean. This research contributes to a better understanding of silica spherules in polar marine environments and their implications for past climate conditions.

Cosmic-ray physics at the South Pole

The geographic South Pole provides unique opportunities to study cosmic particles in the Southern Hemisphere. It represents an optimal location to deploy large-scale neutrino telescopes in the deep Antarctic ice, such as AMANDA or IceCube. In both cases, the presence of an array, constructed to observe extensive air showers, enables hybrid measurements of cosmic rays. While additional neutron monitors can provide information on solar cosmic rays, large detector arrays, like SPASE or IceTop, allow for precise measurements of cosmic rays with energies above several 100TeV. In coincidence with the signals recorded in the deep ice, which are mostly due to the high-energy muons produced in air showers, this hybrid detector setup provides important information about the nature of cosmic rays.In this review, we will discuss the historical motivation and developments towards measurements of cosmic rays at the geographic South Pole and highlight recent results reported by the IceCube Collaboration. We will emphasize the important contributions by Thomas K. Gaisser and his colleagues that ultimately led to the rich Antarctic research program which today provides crucial insights into cosmic-ray physics.

New Genera, Species, and observations on the biology of Antarctic Valvatida (Asteroidea).

Assessment of Antarctic taxonomic diversity for asteroids and other taxa for poorly studied or unknown regions, such as the deep-sea, will be important for our understanding of these understudied habitats. Eleven new species and a new genus are described from three families (Asterinidae, Goniasteridae, Solasteridae) within the Valvatida, nearly all of which were collected from deep-sea settings below 1000 m by the US Antarctic Research Program in the 1960s. A new subfamily, the Kampylasterinae subfam. nov. is designated for Kampylaster and Astrotholus nov. gen. which were supported as sister taxa on a monophyletic clade within the Asterinidae. Astrotholus nov. gen. is described to accommodate "Anseropoda" antarctica and four new bathyal and abyssal species, which are a significant morphological divergence from the typological definition of Anseropoda. New species of the goniasterid Notioceramus and the solasterid Paralophaster are also described from bathyal depths (2000-3000 m). Paralophaster ferax n. sp. is among the deepest asteroids known to brood, is the first brooding species within Paralophaster and the second species in the Solasteridae known to brood. Following examination of the type and molecular data, Lophaster densus is found to be included within Paralophaster. A review of Antarctic Lophaster species shows additional specimens of Lophaster abbreviatus which support it as a distinct species from Lophaster stellans. New occurrence data for bathyal Antarctic Asteroidea as well as unusual-gut content observations of shallower-water species are also included.

Sea Tide Influence on Ice Flow of David Drygalski’s Ice Tongue Inferred from Geodetic GNSS Observations and SAR Offset Tracking Analysis

David Glacier and Drygalski Ice Tongue are massive glaciers in Victoria Land, Antarctica. The ice from the East Antarctic Ice Sheet is drained through the former, and then discharged into the western Ross Sea through the latter. David Drygalski is the largest outlet glacier in Northern Victoria Land, floating kilometers out to sea. The floating and grounded part of the David Glacier are the main focus of this article. During the XXI Italian Antarctic Expedition (2005–2006), within the framework of the National Antarctic Research Programme (PNRA), two GNSS stations were installed at different points: the first close to the grounding line of David Glacier, and the second approximately 40 km downstream of the first one. Simultaneous data logging was performed by both GNSS stations for 24 days. In the latest data processing, the kinematic PPP technique was adopted to evaluate the dominant diurnal components and the very small semi-diurnal variations in ice motion induced by the ocean tide and the mean ice flow rates of both GNSS stations. Comparison of the GNSS time series with predicted ocean tide calculated from harmonic coefficients of the nearest tide gauge stations, installed at Cape Roberts and Mario Zucchelli Station, highlight different local response of the glacier to ocean tide, with a minor amplitude of vertical motion at a point partially anchored at the bedrock close to the grounding line. During low tide, the velocity of the ice flow reaches its daily maximum, in accordance with the direction of seawater outflow from the fjord into the ocean, while the greatest daily tidal excursion generates an increase in the horizontal ice flow velocity. With the aim to extend the analysis in spatial terms, five COSMO-SkyMED Stripmap scenes were processed. The comparison of the co-registered offset tracking rates, obtained from SAR images, with the GNSS estimation shows good agreement.

Antarctic science in Chile: a bibliometric analysis of scientific productivity during the 2009–2019 period

AbstractThe changes implemented in 2005 in the development strategies of Antarctic science carried out by Chile have had a positive impact on the scientific productivity of the Chilean Antarctic Science Program (PROCIEN). We analysed scientometric indicators from between 2009 and 2019. The bibliographic data were extracted from the Web of Science database using search query keywords. We used multiple correspondence analysis to identify specific trends and also network analyses of international collaboration in VOSviewer. The number of Antarctic science publications in Chile has gradually increased from 21 in 2009 to 95 in 2019. The rise in the number of articles was higher in journals for the first impact factor quartile. Research lines showing increased first-quartile impact factor papers corresponded to Antarctic ecosystems, biotechnology and geosciences. The main geographical domains in which such research activities have been carried out corresponded to in the South Shetland Islands and the Antarctic Peninsula. Fieldwork data are the main sources for the production of scientific articles, and there are three science platforms within which most of these papers concentrate. The diversification of funding sources, the implementation of improvements in the selection process and Chile's alignment with Scientific Committee on Antarctic Research programmes have contributed to improving the science that Chile has developed in Antarctica.

Impact of the selected boundary layer schemes and enhanced horizontal resolution on the Weather Research and Forecasting model performance on James Ross Island, Antarctic Peninsula

The output of the various Weather Research and Forecasting (WRF) model configurations was compared with ground-based observations in the northern part of James Ross Island, Antarctic Peninsula. In this region, a network of automatic weather stations deployed at ice-free sites (as well as small glaciers) is operated by the Czech Antarctic Research Programme. Data from these stations provide a unique opportunity to evaluate the WRF model in a complex terrain of James Ross Island. The model was forced by the ERA5 reanalysis data and the University of Bremen sea ice data. The model configurations include a novel Three-Dimensional Scale-Adaptive Turbulent Kinetic Energy (3D TKE) planetary boundary layer scheme and a more traditional Quasi-Normal Scale Elimination (QNSE) scheme. Impact of model horizontal resolution was evaluated by running simulations in both 700 m and 300 m. The validation period, 25 May 2019 to 12 June 2019, was selected to cover different stratification regimes of air temperature and a significant snowfall event. Air temperature was simulated well except for strong low-level inversions. These inversions occurred in 44% of all cases and contributed to a higher mean bias (2.0–2.9°C) at low-elevation sites than at high altitude sites (0.2–0.6°C). The selection of the 3D TKE scheme led to improvement at low-elevation sites; at high altitude sites, the differences between model configurations were rather small. The best performance in wind speed simulation was achieved with the combination of the 3D TKE scheme and 300 m model resolution. The most important improvement was decrease of bias at a coastal Mendel Station from 3.5 m·s‑1 with the QNSE scheme on the 700 m grid to 1.2 m·s‑1 with the 3D TKE scheme on the 300 m grid. The WRF model was also proven to simulate a large snowfall event with a good correspondence with the observed snow height.

A COMBINED APPROACH FOR LONG-TERM MONITORING OF BENTHOS IN ANTARCTICA WITH UNDERWATER PHOTOGRAMMETRY AND IMAGE UNDERSTANDING

Abstract. Long-term monitoring projects are becoming more than ever crucial in assessing the effects of climate change on marine communities, especially in Antarctica, where these changes are expected to be particularly dramatic. Detailed studies of the Antarctic benthos are in fact particularly important for a better understanding of benthos dynamics and potential climate-driven shifts. Here, due to the extreme fragility of benthic communities, non-destructive techniques represent the best solution in long-term monitoring programs. In this paper we report new results from 2017, 2018, 2019 photogrammetric campaigns within the Italian National Antarctic Research Program (PNRA). A new protocol of data acquisition and multi-temporal processing that provides co-registered 3D point clouds between the three years without control points nor direct georeferencing methods is presented. This is achieved by adding a level of image understanding leveraging semantic segmentation with convolutional neural network (CNN) of the benthic features. Slow growing (estimated less than a mm per year) organisms, such as Corallinales (Rhodophyta algae), represent a natural stable pattern, leveraged to automatically orient in the same reference system the photogrammetric surveys of different epochs. This approach is also proved to be effective in improving the orientation of adjacent strips acquired within the same campaign. Within the paper an in depth analysis of the achieved results shows the effectiveness of the implemented procedure.

Chaetarcturus cervicornis sp. n., a New Ross Sea Isopod of the Genus Chaetarcturus Brandt, 1990 (Crustacea, Malacostraca)

In the framework of the PNRA (Italian National Antarctic Research Program) project CARBONANT focusing on biogenic carbonates and held in January–February 2002, several Ross Sea banks were sampled to obtain samples of biogenic carbonates. In the Mawson Bank, species belonging to the isopod genus Chaetarcturus Brandt, 1990 were recorded, including a specimen that did not match any described species. In this paper we describe Chaetarcturus cervicornis sp. n., which is characterized by supraocular spines and two pairs of tubercle-like protrusions on the cephalothorax. The new species is very similar to C. bovinus (Brandt & Wägele, 1988) and C. adareanus (Hodgson, 1902), but has a clearly different spine pattern. The study of the species of the genus Chaetarcturus in the Ross Sea contributes to increase our knowledge on the diversity of the Antarcturidae in the Southern Ocean. Ross Sea banks seem to hold an interesting and not-well-known fauna, deserving attention in future research.

Bioactivity Screening of Antarctic Sponges Reveals Anticancer Activity and Potential Cell Death via Ferroptosis by Mycalols.

Sponges are known to produce a series of compounds with bioactivities useful for human health. This study was conducted on four sponges collected in the framework of the XXXIV Italian National Antarctic Research Program (PNRA) in November-December 2018, i.e., Mycale (Oxymycale) acerata, Haliclona (Rhizoniera) dancoi, Hemimycale topsenti, and Hemigellius pilosus. Sponge extracts were fractioned and tested against hepatocellular carcinoma (HepG2), lung carcinoma (A549), and melanoma cells (A2058), in order to screen for antiproliferative or cytotoxic activity. Two different chemical classes of compounds, belonging to mycalols and suberitenones, were identified in the active fractions. Mycalols were the most active compounds, and their mechanism of action was also investigated at the gene and protein levels in HepG2 cells. Of the differentially expressed genes, ULK1 and GALNT5 were the most down-regulated genes, while MAPK8 was one of the most up-regulated genes. These genes were previously associated with ferroptosis, a programmed cell death triggered by iron-dependent lipid peroxidation, confirmed at the protein level by the down-regulation of GPX4, a key regulator of ferroptosis, and the up-regulation of NCOA4, involved in iron homeostasis. These data suggest, for the first time, that mycalols act by triggering ferroptosis in HepG2 cells.

A Metataxonomic Approach Reveals Diversified Bacterial Communities in Antarctic Sponges.

Marine sponges commonly host a repertoire of bacterial-associated organisms, which significantly contribute to their health and survival by producing several anti-predatory molecules. Many of these compounds are produced by sponge-associated bacteria and represent an incredible source of novel bioactive metabolites with biotechnological relevance. Although most investigations are focused on tropical and temperate species, to date, few studies have described the composition of microbiota hosted by Antarctic sponges and the secondary metabolites that they produce. The investigation was conducted on four sponges collected from two different sites in the framework of the XXXIV Italian National Antarctic Research Program (PNRA) in November–December 2018. Collected species were characterized as Mycale (Oxymycale) acerata, Haliclona (Rhizoniera) dancoi, Hemigellius pilosus and Microxina sarai by morphological analysis of spicules and amplification of four molecular markers. Metataxonomic analysis of these four Antarctic sponges revealed a considerable abundance of Amplicon Sequence Variants (ASVs) belonging to the phyla Proteobacteria, Bacteroidetes, Actinobacteria and Verrucomicrobia. In particular, M. (Oxymycale) acerata, displayed several genera of great interest, such as Endozoicomonas, Rubritalea, Ulvibacter, Fulvivirga and Colwellia. On the other hand, the sponges H. pilosus and H. (Rhizoniera) dancoi hosted bacteria belonging to the genera Pseudhongella, Roseobacter and Bdellovibrio, whereas M. sarai was the sole species showing some strains affiliated to the genus Polaribacter. Considering that most of the bacteria identified in the present study are known to produce valuable secondary metabolites, the four Antarctic sponges could be proposed as potential tools for the discovery of novel pharmacologically active compounds.

Chapter 7.3 Mount Melbourne and Mount Rittmann

Abstract Mount Melbourne and Mount Rittmann are quiescent, although potentially explosive, alkaline volcanoes located 100 km apart in Northern Victoria Land quite close to three stations (Mario Zucchelli Station, Gondwana and Jang Bogo). The earliest investigations on Mount Melbourne started at the end of the 1960s; Mount Rittmann was discovered during the 1988–89 Italian campaign and knowledge of it is more limited due to the extensive ice cover. The first geophysical observations at Mount Melbourne were set up in 1988 by the Italian National Antarctic Research Programme (PNRA), which has recently funded new volcanological, geochemical and geophysical investigations on both volcanoes. Mount Melbourne and Mount Rittmann are active, and are characterized by fumaroles that are fed by volcanic fluid; their seismicity shows typical volcano signals, such as long-period events and tremor. Slow deformative phases have been recognized in the Mount Melbourne summit area. Future implementation of monitoring systems would help to improve our knowledge and enable near-real-time data to be acquired in order to track the evolution of these volcanoes. This would prove extremely useful in volcanic risk mitigation, considering that both Mount Melbourne and Mount Rittmann are potentially capable of producing major explosive activity with a possible risk to large and distant communities.

The harmonization of small-scale marine spatial protection in the Argentine Islands area (Antarctic Peninsula) under the Antarctic Treaty System

The purpose of the article is to summarize the results of field studies carried out in the framework of the State Antarctic Research Program for 2011–2020 and undertaken to identify areas of special interest for small-scale marine spatial protection in the Argentine Islands water area. The scientific results reported in the publications and relevant meetings’ documents officially presented by the Ukrainian delegation in 2012–2019 were summarized and interpreted in view of the Antarctic Treaty System (ATS) provisions on marine spatial protection. GIS analysis was applied to field data. It is shown that the development of protection regime for small-scale underwater landscape is based on systematic biogeographical data collected during seasonal and year-round Ukrainian Antarctic expeditions in 2011–2019. In order to harmonize the application of all available tools of spatial ecosystem-based protection across the ATS, it is proposed to designate the long-term environmental monitoring sites around Ukrainian Antarctic Akademik Vernadsky station as a new Antarctic Specially Protected Area (ASPA) consisting of terrestrial and marine components. It is shown that the marine component of the proposed ASPA could serve as one of the scientific reference areas of the broad-scale Marine Protected Area in Domain 1 within the Antarctic Peninsula region for assessing the impact of climate change on benthic communities, as well as breeding success and distribution of penguin colonies.

Species of Acryptolaria Norman, 1875 (Cnidaria: Hydrozoa) collected by US Antarctic and sub-Antarctic expeditions.

Acryptolaria is a worldwide genus of deep-water benthic hydroids. The genus has relatively high species diversity, with 36 species described so far, yet most of them have been reported only occasionally. As a result, scientific knowledge of their ecology and distribution is scarce. Here I present the results of the study of species of Acryptolaria collected during several Antarctic and sub-Antarctic expeditions under the United States Antarctic Research Program between 1958 and 1986. Eight species were found in the collection (plus one determined to the genus level), with A. operculata having the highest occurrence. Acryptolaria flabellum is reported for the second time; the study also represents the third record for A. corniformis and A. minuta. Despite the scarcity of records, most of the species studied seem to have a wide geographical distribution, which could be related to their deep-water bathymetric distribution and the deep-water circulation of the Great Ocean Conveyor Belt.

Evaluating governance of national Antarctic programme: Universities' role in influencing the evolution of Malaysia's engagement on cross-border research of the Antarctic

National Antarctic Programmes (NAPs) need to keep an open mind regarding the effective governance arrangement because they involve complex international bodies and instruments of the Antarctic, and the multiple stakeholders involved at the domestic level. Without a proper setting, country's involvement in this kind of cross-border science programmes and international research collaborations would be a daunting task. Through qualitative approaches, this case study aims to evaluate the domestic governance of Malaysian Antarctic Research Programme (MARP). The result revealed that MARP has passed through several distinct stages of transformations in governance, and researchers from local universities have played significant roles. Several recommendations have been pointed out to reinforce MARP's domestic governance; a part of it to explore potential of public-private partnership and Quadruple Helix (Academia-driven) in diversifying financial resources and intensifying national interests. This study draws lessons from policy learning on a non-traditional Antarctic player trying to govern and sustain its NAP with limited resources; experiences and best practices in engaging cross-border research involving arrangement of multi-level governance; and capacity of university and its researchers in influencing policy-making process of the national research programme.

Dynamics of Accumulative Coasts in Enclosed Bays of Antarctica (with an Example of the Key Area of the South Georgia Microcontinent)

The object of direct study is the accumulative coast of King Edward Bay on the island of South Georgia of the Antarctic microcontinent of the same name. Neotectonic uplift of the island is causing accumulative coastal processes in the conjugate zone between land and sea in areas with relative tectonic subsidence. Geological and geomorphological studies and mathematical modeling of the coastal zone lithodynamics make it possible to identify the main factors of its current state and substantiate the forecast for development in the 21st century. The choice of object is dictated by the demand for different information with respect to its association with the area of active international tourism and the possibility of obtaining original geological and geomorphological material under the Shirshov Institute of Oceanology’s Antarctic research program.

The Bryozoa collection of the Italian National Antarctic Museum, with an updated checklist from Terra Nova Bay, Ross Sea.

This study provides taxonomic and distributional data of bryozoan species from the Ross Sea area, mainly around Terra Nova Bay, based on specimens curated at the Italian National Antarctic Museum (MNA, Section of Genoa). Bryozoan specimens were collected at 75 different sampling stations in the Ross Sea and in the Magellan Strait, in a bathymetric range of 18–711 meters, during 13 expeditions of the Italian National Antarctic Research Program (PNRA) conducted between 1988 and 2014. A total of 282 MNA vouchers corresponding to 311 specimens and 127 morphospecies have been identified and included in the present dataset. 62% of the species were already reported for the Terra Nova Bay area, where most of the Italian samples come from, with a 35% of samples representing new records classified at the specific level, and 3% classified at the genus level. These new additions increase to 124 the total number of species known to occur in Terra Nova Bay. Four 3D-models of Antarctic bryozoans from the Ross Sea are also presented and will be released for research and educational purposes on the Museum website.

Science in the snow. Sixty years of international collaboration through the Scientific Committee on Antarctic Research. David W. H. Walton, Peter D. Clarkson and Colin P. Summerhayes. 2018. Cambridge: Scientific Committee on Antarctic Research with Victoria Press. xi + 321 p, illustrated, paperback, ISBN 978-0-948277-55-9 (limited edition) (e-Book ISBN 978-0-948277-56-6).

This richly illustrated book gives an account of the evolution of SCAR from the time of its birth in 1958 in the wake of the International Geophysical Year (IGY 1957–58) up to and including its 60th birthday. It is the second (now expanded) edition of a book previously issued in connection with the organisation’s 50th birthday. The primary focus is on the inner life of SCAR, its structure, and its purpose in bringing together members of national scientific communities to plan, coordinate and collaborate through Antarctic research programmes. The reader is provided with detailed descriptions of the science done and how research agendas, themes, as well as priorities have changed over time, plus how results were and are disseminated. Apart from being a mine of information that will interest many scientists and amongst some of these trigger memories of times past, the present volume is an invaluable sourcebook for historians and social scientists concerned with analysing changing trends in Antarctic research. With its fount of facts and data it may also serve as a point of departure for oral history projects.

Porifera collection of the Italian National Antarctic Museum (MNA), with an updated checklist from Terra Nova Bay (Ross Sea).

This new dataset presents occurrence data for Porifera collected in the Ross Sea, mainly in the Terra Nova Bay area, and curated at the Italian National Antarctic Museum (MNA, section of Genoa). Specimens were collected in 331 different sampling stations at depths ranging from 17 to 1,100 meters in the framework of 17 different Italian Antarctic expeditions funded by the Italian National Antarctic Research Program (PNRA). A total of 807 specimens, belonging to 144 morphospecies (i.e., 95 taxa identified at species level and 49 classified at least at the genus level) is included in the dataset. Nearly half (45%) of the species reported here correspond to species already known for Terra Nova Bay. Out of the remaining 55% previously unknown records, under a third (~29%) were classified at the species level, while over a quarter (~26%) were ascribed to the genus level only and these would require further study. All vouchers are permanently curated at the MNA and are available for study to the scientific community. A 3D model of an uncommon species from the Ross Sea, i.e. Tethyopsisbrondstedi (Burton, 1929), is also presented and will be made available for outreach purposes.

Analysis of multi-year near-surface ozone observations at the WMO/GAW “Concordia” station (75°06′S, 123°20′E, 3280 m a.s.l. – Antarctica)

This work focuses on the near-surface O3 variability over the eastern Antarctic Plateau. In particular, eight years (2006–2013) of continuous observations at the WMO/GAW contributing station “Concordia” (Dome C–DMC: 75°06′S, 123°20′E, 3280 m) are presented, in the framework of the Italian Antarctic Research Programme (PNRA). First, the characterization of seasonal and diurnal O3 variability at DMC is provided. Then, for the period of highest data coverage (2008–2013), we investigated the role of specific atmospheric processes in affecting near-surface summer O3 variability, when O3 enhancement events (OEEs) are systematically observed at DMC (average monthly frequency peaking up to 60% in December). As deduced by a statistical selection methodology, these OEEs are affected by a significant interannual variability, both in their average O3 values and in their frequency. To explain part of this variability, we analyzed OEEs as a function of specific atmospheric variables and processes: (i) total column of O3 (TCO) and UV-A irradiance, (ii) long-range transport of air masses over the Antarctic Plateau (by Lagrangian back-trajectory analysis – LAGRANTO), (iii) occurrence of “deep” stratospheric intrusion events (by using the Lagrangian tool STLEFLUX). The overall near-surface O3 variability at DMC is controlled by a day-to-day pattern, which strongly points towards a dominating influence of processes occurring at “synoptic” scales rather than “local” processes. Even if previous studies suggested an inverse relationship between OEEs and TCO, we found a slight tendency for the annual frequency of OEEs to be higher when TCO values are higher over DMC. The annual occurrence of OEEs at DMC seems related to the total time spent by air masses over the Antarctic plateau before their arrival to DMC, suggesting the accumulation of photochemically-produced O3 during the transport, rather than a more efficient local production. Moreover, the identification of recent (i.e., 4-day old) stratospheric intrusion events by STEFLUX suggested only a minor influence (up to 3% of the period, in November) of “deep” events on the variability of near-surface summer O3 at DMC.

Metal complexation capacity of Antarctic lacustrine sediments

The purpose of this study is to implement a work that is a part of a project funded by the Italian National Antarctic Research Program (PNRA, Piano Nazionale di Ricerche in Antartide) within the main thematic focus “Chemical Contamination-Global Change”. This research was devoted to detect and characterize micro and nano components with strong complexing capability towards metal ions at trace level in sea water, lakes and lacustrine sediments, sampled during the XXII expedition of PNRA.In particular, in the present work, the sorption complexation capacity of an Antarctic lacustrine sediments toward Cu(II) and Pb(II) is described. The characterization of the sorption was undertaken, studying kinetics and isotherm profiles. The lake here considered is Tarn Flat in the area of Terra Nova Bay. The sorption equilibria of Cu(II) and Pb(II) on the lacustrine sediments were reached in about 10 h, and they were best modelled by the Langmuir equation.Preliminary, to establish if the data here obtained were consistent with those reported for the same area in other expeditions, a common multivariate techniques, namely the principal component analysis (PCA), was applied and finally the consistency of the data has been confirmed.